Method of mounting a roof construction in a cistern



April 28, 1964 G. LINDSTRUM 3,130,438

METHOD OF MOUNTING A ROOF CONSTRUCTION IN A CISTERN Filed Feb. 17. 1961 INVENTOR I Georg Lindsrrb'm y mdz K v I ATTORNEYS United States Patent 3,130,488 METHQD 0F MOUNTENG A ROOF CONSTRUC- TION IN A CISTERN Georg Lindstriim, Arboga, Sweden, assigns: to Sveremo Aktiebolag, Arhoga, Sweden Filed Feb. 17, 1961, Ser. No. 90,023 3 Claims. (ill. 29-428) This application is a continuation-in-part of my application Serial No. 795,138 filed February 24, 1959, now abandoned entitled Roof Construction and Method of Mounting It.

The present invention relates to a method of mounting roof constructions in cylindrical above ground and underground cisterns and like reservoirs.

Theprincipal object of the invention is to provide a method of mounting roof construction having a tie member extending all around the circumference of the roof construction. The tie member which may be a band, a cable or the like reduces the load of the roof construction on the cistern proper and also favorably distributes said load.

Another object of the invention is to provide a method of mounting roof construction comprising a number of equally long and regularly distributed beams which project radially outwardly from a center, the tie member extending between the beam ends remote from said center. The portions of the tie member located between the beam ends are straight so that the tie member constitutes the circumference of a regular polygon.

Still another object of the invention is to provide a method of mounting the roof construction on a cylindrical cistern of such a size that the ends of the radially outwardly projecting beamsremote from the center, together with the tie member attached to said beam ends, substantially reach the internal circumferential surface of the cistern, the roof construction being raised within the cistern for instance by buoyancy substantially to the level that it is to occupy in mounted position. The method is substantially characterized by the steps of mounting roof construction supporting brackets at the internal circumferential surface of the cistern in the spaces existing between said circumferential surface and the tie member halfway between the beam ends, rotating the roof construction so that the beam ends register with the brackets, and then securing the beam ends to said brackets.

Further objects of the invention and the advantages gained thereby will appear from the following description, reference being had to the accompanying drawings which illustrate an embodiment, chosen by way of example, of the roof construction when mounted on a cylindrical cistern, in which FIGURE 1 is a cross-sectional View illustrating a cistern and a roof mounted thereon,

FIGURE 2 is a plan view of a part of the roof construction,

FIGURE 3 is a cross-sectional view on a larger scale showing one of the points for fixing the roof construction to the cistern shown in FIGURE 1, and

FIGURE 4 is an elevational view of one of the brackets used for supporting the roof.

With reference to the embodiment illustrated, the roof construction 1 comprises a number of equally long and regularly distributed beams 3 projecting radially outwardly from a central ring 2. The beams 3 which preferably are U-beams are laterally stayed by annularly extending transverse beams 4. Beams 5 together form a torsional bracing. In a preferred embodiment the entire roof construction 1 comprises four such torsional bracings, which are regularly distributed in the roof construction.

According to the invention the roof construction 1 has 3,13%,433 Patented Apr. 28, 1964 a tie member 6 which extends all around the circumference of the roof construction and which in the illustrated embodiment is a tie band of ilat iron or the like. The tie member 6 may also be a cable or the like.

In the illustrated, preferred roof construction the tie member 6 extends between the ends 7 of the beams 3 remote from the central ring 2, the portions of the tie member 6 located between the beam ends 7 being straight so that the tie member 6 constitutes the circumference of a regular polygon.

The roof construction 1 is mounted on a cylindrical cistern 8 of such a size that the ends 7 of the radially outwardly projecting beams 3, together with the tie member 6 secured thereto, substantially reach the internal circumferential surface of the cistern 8. Welded to said circumferential surface are brackets 9 or the like, on which the roof construction 1 is supported by the ends 7 of the beams 3.

Upon erection the roof construction 1 is raised within the cistern 8 substantially to the level it is to occupy in mounted position. According to a preferred method said raising of the roof construction is effected by buoyancy. At an early stage of the mounting of the cistern 8 the roof construction 1 is finished within the cistern 8, whereupon the roof construction 1 is used as a platform for the continued mounting by equipping it with pontoons which float on water supplied to the cistern 8. The level of the water is elevated according as the mounting proceeds so that the roof construction 1 serving as a working platform always is at a height convenient to the mounting work. At an early stage of the mounting the roof construction 1 must therefore be provided with a number of roofing plates which serve as a platform. During mounting the roof construction 1 is easily rotated in the cistern 8.

According to the invention, the brackets 9 are arranged on the internal circumferential surface of the cistern 8 in the spaces 1%) existing between said surface and the tie member 6 halfway between the beam ends 7, whereafter the roof construction 1 is rotated so that the beam ends 7 will register with the brackets 9 to which they are then secured by welding or by a nut and bolt connection later described. The fixation of the brackets 9 can take place before or after the roof construction 1 has been raised to its final position.

When the beam ends 7 are welded to the brackets 9 the construction so obtained has only a limited range of use. Thus it can be used only in cisterns that are subject to vacuum and have no pressure and vacuum valve. On the other hand the fixation shown in FIGURES 3 and 4 and described below will be more generally employed since it is so designed that the roof will have the possibility of naturally expanding and contracting in response to the relatively large temperature changes to which it may be exposed normally.

As seen in FIGURES 3 and 4, a plate 13 is welded to the end 7 of a beam 3. This plate is adapted to rest on the bracket 9, the connection being formed by a bolted union including the bolt 14, the nut 15 and the washer 16. The bolt 14 is engaged in a slot 17 extending longitudinally of the beam 3 in the upper part 18 of the bracket 9. The slot 17 should preferably be located in the middle of the upper bracket part 18, and the bracket 9 therefore is provided with two lateral guide members 19, as will appear from FIGURE 4.

An L-iron 12 extends all around the cistern 8 at the top edge thereof and serves to increase the strength of the cistern 8.

While the invention has been described in the foregoing and illustrated in the drawing with reference to a preferred embodiment, it is understood that the invention is not limited to this very embodiment and that many modifications may be resorted to within the scope of the appendant claims.

I claim:

1. A method of mounting a roof construction adapted to float in a cylindrical cistern said roof construction having radial beams that extend from the center of the roof construction substantially to the internal circumferential surface of the cistern, the outer ends of adjacent radial beams being secured together by straight tie members whereby the midpoint of each tie member is spaced from the internal circumferential surface of the cistern and wherein the ends of the radially outwardly projecting beams remote from the center, together with the tie member attached to said beam ends, substantailly reach the internal circumferential surface of the cistern and the roof ber attached to said beam ends, substantially reach the internal circumferential surface of the cistern and the roof construction within the cistern is raised by buoyancy caused by filling the cistern with fluid substantially to the level it is to occupy in mounted position, comprising raising the roof construction within the cistern by buoyancy caused by filling the cistern with fluid, mounting roof construction supporting brackets on the internal circumferential surface of the cistern in the spaces existing between said circumferential surface and the tie member halfway between the beam ends, rotating the roof construction so that the beam ends register with said brackets, and then securing the beam ends to said brackets.

2. A method of mounting a roof construction adapted to float in a cylindrical cistern said roof construction having radial beams that extend from the center of the roof construction substantially to the internal circumferential surface of the cistern, the outer ends of adjacent radial beams being secured together by straight tie members whereby the midpoint of each tie member is spaced from the internal circumferential surface of the cistern and wherein the ends of the radially outwardly projecting beams remote from the center, together with the tie member attached to said beam ends, substantially reach the internal circumferential surface of the cistern and the roof construction Within the cistern is raised by bouyancy caused by filling the cistern With fluid substantially to the level it is to occupy in mounted position, comprising raising the roof construction within the cistern by buoyancy caused by filling the cistern with fluid, mounting roof construction supporting brackets on the internal circumferential surface of the cistern in the spaces existing between said circumferential surface and the tie member halfway between the beam ends, rotating the roof construction so that the beam ends register with said brackets, and then securing the beam ends adjustably to said brackets.

3. A method of mounting a roof construction adapted to float in a cylindrical cistern said roof construction having radial beams that extend from the center of the roof construction substantially to the internal circumferential surface of the cistern, the outer ends of adjacent radial beams being secured together by straight tie members whereby the midpoint of each tie member is spaced from the internal circumferential surface of the cistern and comprising mounting roof construction supporting brackets on the internal circumferential surface of the cistern in the space existing between said circumferential surface and the tie member halfway between the beam ends raising the roof construction within said cistern by buoyancy caused by filling the cistern with fluid substantially to the level it is to occupy in mounted position and then rotating said roof so that the ends of the beams in said roof will register with brackets provided upon the internal surface of the cistern.

References Cited in the file of this patent UNITED STATES PATENTS 1,792,356 Boiseau Feb. 10, 1931' 1,852,659 Kramer Apr. 5, 1932 2,073,358 Williamson Mar. 9, 1937 2,355,874 Laird Aug. 15, 1944 7 2,766,707 Foster et al. Oct. 6, 1956 2,773,458 Foster et al. Dec. 11, 1956 2,848,799 Hanna Aug. 26, 1958 2,849,792 Wiggins Sept. 2, 1958 

1. A METHOD OF MOUNTING A ROOF CONSTRUCTION ADAPTED TO FLOAT IN A CYLINDRICAL CISTERN SAID ROOF CONSTRUCTION HAVING RADIAL BEAMS THAT EXTEND FROM THE CENTER OF THE ROOF CONSTRUCTION SUBSTANTIALLY TO THE INTERNAL CIRCUMFERENTIAL SURFACE OF THE CISTERN, THE OUTER ENDS OF ADJACENT RADIAL BEAMS BEING SECURED TOGETHER BY STRAIGHT TIE MEMBERS WHEREBY THE MIDPOINT OF EACH TIE MEMBER IS SPACED FROM THE INTERNAL CIRCUMFERENTIAL SURFACE OF THE CISTERN AND WHEREIN THE ENDS OF THE RADIALLY OUTWARDLY PROJECTING BEAMS REMOTE FROM THE CENTER, TOGETHER WITH THE TIE MEMBER ATTACHED TO SAID BEAM ENDS, SUBSTANTIALLY REACH THE INTERNAL CIRCUMFERENTIAL SURFACE OF THE CISTERN AND THE ROOF CAUSED BY FILLING THE CISTERN WITH FLUID SUBSTANTIALLY TO THE LEVEL IT IS TO OCCUPY IN MOUNTED POSITION, COMPRISING RAISING THE ROOF CONSTRUCTION WITHIN THE CISTERN BY BUOYANCY CAUSED BY FILLING THE CISTERN WITH FLUID, MOUNTING ROOF CONSTRUCTION SUPPORTING BRACKETS ON THE INTERNAL CIRCUMFERENTIAL SURFACE OF THE CISTERN IN THE SPACES EXISTING BETWEEN SAID CIRCUMFERENTIAL SURFACE AND THE TIE MEMBER HALFWAY BETWEEN THE BEAM ENDS, ROTATING THE ROOF CONSTRUCTION SO THAT THE BEAM ENDS REGISTER WITH SAID BRACKETS, AND THEN SECURING THE BEAM ENDS TO SAID BRACKETS. 